The new baby is President Trump's ninth grandchild. First daughter Ivanka Trump and her husband Jared Kushner have three children, and Trump's eldest son, Donald Trump Jr., and wife Vanessa have five children.

Ivanka Trump and Trump Jr. took to Twitter to offer their congratulations to their brother and sister-in-law.

Reactions to Eric and Lara Trump's birth announcement:

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Reactions to Eric and wife Lara's first baby

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Reactions to Eric and wife Lara's first baby

.@LaraLeaTrump and I are excited to announce the birth of our son, Eric "Luke" Trump at 8:50 this morning. https://t.co/b8zRSktcd8

.@LaraLeaTrump and I are excited to announce the birth of our son, Eric "Luke" Trump at 8:50 this morning.

Welcome to the world, baby boy. I can't wait to meet you ❤️ https://t.co/sIkPrFWKO2

Congrats buddy. Welcome to the club. Now that the niceties are out of the way it's older brother revenge for that d… https://t.co/KeNV4NbS3Q

Congratulations to Eric & Lara on the birth of their son, Eric "Luke" Trump this morning! https://t.co/Aw0AV82XdE

Karen & I wish Eric & Lara congratulations on the birth of their new son. https://t.co/o6nO0H2opy